Thermographic phospors in the gas phase

湍流燃烧过程仍将是技术能源转换的基础技术。燃烧技术越来越需要化学、物理和耦合过程的详细知识。特别重要的是要了解流动和温度场。温度和速度的同时测量使其能够将两个参数关联起来。这是需要的标量通量的量化和那些是非常重要的守恒方程，用于simulation.New发展的封闭的鲁棒性和定量的温度测量的基础上的热敏荧光粉（TGP）。TGP是掺杂的无机结晶固体，其光谱特性取决于温度。光谱和时间发射随温度而变化，这用于感官目的。掺杂剂是过渡金属或稀土元素。TGP用于壁的温度测量是非常成功的。加入TGP粉末（粒径约为100 μ m），2 µm）的测量，使其能够使用粒子图像测速仪（PIV）确定温度和流量。这是通过连续记录的两个米氏散射图像的互相关计算来完成的。该方法在温度和速度的联合测量中具有很高的潜力。从早期的研究得出的结论是，PIV和TGP的组合将是非常有用的标量通量的测量在热气体应用和燃烧环境下的以下要求：单次测量的精度必须增加，信噪比高于1000 K必须提高。该方法目前还没有应用于燃烧过程中，因为热动力学和流体动力学的优化与提高信噪比之间存在着矛盾，为了克服这些限制，我们将从两个方面来实现本研究项目的目标：1）从量子效率和截面方面来优化TGP; 2）将合成中空颗粒并针对上述应用进行测试。由于颗粒满足应用所规定的规格非常重要，因此将颗粒应用于燃烧过程的人员必须与合成TGP的专家密切合作。该提案的两个申请人过去都表明他们的合作非常成功。

Combustion processes that are turbulent will remain the base technology of technical energy conversion. A detailed knowledge of chemical, physical and coupled processes is required increasingly for the technologies of combustion. In particular it is important to understand the fields of flow and temperature. Simultaneous measurements of temperature and speed allow it to correlate both parameters. This is needed for the quantification of scalar fluxes and those are of eminent importance for the closing of the conservation equation that is used for the simulation.New developments towards a robust and quantitative temperature measurement are based on thermographic phosphors (TGP). TGPs are doped inorganic, crystalline solids with spectral properties that depend on temperature. The spectral and temporal emission changes with temperature and this is used for sensory purposes. Dopants are transition metals or rare earth elements. The use of TGPs for temperature measurements of the walls has been very successful. Adding TGP powders (particle diameter approx. 2 µm) to a fluid (gas or liquid) allows it to determine the temperature and the flow using particle image velocimetry (PIV). This is done by cross-correlation calculations of two Mie scattering images recorded consecutively. This method is of high potential for combined measurements of temperature and speed. From earlier studies it is concluded that the combination of PIV and TGPs will be very useful for measurements of scalar fluxes in hot gas applications and combustion environments under the following requirements: The precision for single shot measurements has to be increased and the signal-to-noise ratio above 1000 K has to be enhanced. The method is not yet used in combustion processes because there is a conflict of goals between the optimization of thermal and fluid dynamics and an enhancement of the signal-to-noise ratio.To overcome these limitations we will approach the goal of this research project on two tracks: 1) The TGPs will be optimized concerning quantum efficiency and cross section; 2) Hollow particles will be synthesized and tested for the application described above. Since it is very important that the particles fulfil the specifications dictated by the application it is mandatory that those who apply the particles to the combustion process collaborate closely with the experts that synthesize the TGPs. Both applicants of this proposal have shown in the past that their collaboration is very successful.